A conventional smartphone holder is configured to support a smartphone or a tablet, but as charging electricity to the smartphone or the tablet, a data transfer cable cannot be retracted into the conventional smartphone holder, thus damaging the data transfer cable easily.
The data transfer cable is pulled out of a casing of a conventional transfer cable roller and is retraced into the transfer cable roller by using a spiral torsion spring fixed in the transfer cable roller. However, the conventional transfer cable roller cannot support the smartphone.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.